It's actually a misconception to blame the Brit magazine explosions at Jutland on either a lack of flash-tight features or a careless failure to use those that existed. Similarly, it's a misconception to say that the Germans didn't blow up just because they had either better flash-tight equipment or used what they had. At the bottom line, the real reason that the Brits had main magazine explosions and the Germans didn't was the different chemical composition of their main gun propellants.
Brit cordite was hellish stuff that burned extremely rapidly, and this quickly produced massive, ship-rupturing gas overpressures, even when in the relatively open air of magazines instead of gun breeches, and even with relatively small amounts of cordite involved. German propellant, OTOH, didn't burn nearly so rapidly outside the guns, and thus did not produce the gas overpressures that tore the Brit ships apart. Thus, it really didn't matter how the Brits handled their cordite or what flash-tight features they put in their ships. Once cordite got burning anywhere along its path in a main turret, the ship was almost certainly doomed. German ships, OTOH, survived propellant fires inside the main magazines themselves.
Here are some examples to illustrate this:
Seydlitz at Dogger Bank
When both aft turrets burned out, over 6 tons of propellant went up in smoke, including some in the magazines themselves, not just in the hoists and working chambers. There was no explosion, just a big fire. There was more exposed propellant than there should have been, but that just increased the likelihood of the fire starting in the 1st place. The ship was never in any danger of sinking from this propellant fire by itself, because it didn't produce the gas pressure necessary to burst the ship's structure. The Germans were concerned that the heat from the fire in the main propellant magazines might cook off the shells stored on the deck above, not that the propellant itself would rip the ship apart.
Lion at Jutland
Fortunately for the Brits, the initial hit did not ignite any cordite. By the time the cordite did ignite about 20 minutes later, the magazines had been flooded. Thus, the fire only involved 6 or 8 charges, only about 1/10 of the amout of propellant involved in the Seydlitz fire, all of which were in hoist cages or protected waiting positions--no excess cordite lying around exposed. Yet the gas overpressure caused by the ignition of this small amount of cordite blew part of the turret armor off and seriously deformed the magazine bulkheads, even though the explosion was partially vented by the turret already missing a large chunk. If the magazines had not already been flooded, the ship certainly would have been blown in half. Even if the magazine doors had been closed and flash-tight from the outside in (which they weren't), the overpressure of just a few charges in the hoists would have pushed the doors aside and exposed unflooded magazines to flash.
WW2
It should be noted that even with the slightly less-dangerous WW2 version of cordite, and with all the flash-tight advances implemented since Jutland, Hood still blew up from a cordite magazine explosion (sorry JD). OTOH, when a bomb lit off Gneisenau's forward main magazine, over 23 tons of propellant burned (nearly 4x what Seydltiz suffered), all of which was in the magazine. Yet there was no explosion.